<template>
        <el-table :data="formatData" row-key="id" :row-style="showRow" v-bind="$attrs" v-loading="loading">
          <el-table-column v-if="columns.length===0" width="150">
            <template slot-scope="scope">
              <span v-for="space in scope.row._level" :key="space" class="ms-tree-space"/>
              <span v-if="iconShow(0,scope.row)" class="tree-ctrl" @click="toggleExpanded(scope.$index)">
                <i v-if="!scope.row._expanded" class="el-icon-plus"/>
                <i v-else class="el-icon-minus"/>
              </span>
              <!-- {{ scope.$index }} -->
            </template>
          </el-table-column>
          <el-table-column v-for="(column, index) in columns" v-else :key="column.value" :label="column.text" :width="column.width">
            <template slot-scope="scope">
              <span v-for="space in scope.row._level" v-if="index === 0" :key="space" class="ms-tree-space"/>
              <span v-if="iconShow(index,scope.row)" class="tree-ctrl" @click="toggleExpanded(scope.$index)">
                <i v-if="!scope.row._expanded" class="el-icon-plus"/>
                <i v-else class="el-icon-minus"/>
              </span>
              <!-- {{ scope.row[column.value] }} -->
            </template>
          </el-table-column>
          <slot/>
        </el-table>
      </template>

      <script>
      import treeToArray from './eval'
      export default {
        name: 'TreeTable',
        props: {
          data: {
            type: [Array, Object],
            required: true
          },
          columns: {
            type: Array,
            default: () => []
          },
          childrenKey: {
            type: String,
            default: 'children'
          },
          evalFunc: Function,
          evalArgs: Array,
          expandAll: {
            type: Boolean,
            default: false
          },
          loading: {
            type: Boolean,
            default: false
          },
        },
        computed: {
          // 格式化数据源
          formatData: function() {
            let tmp
            if (!Array.isArray(this.data)) {
              tmp = [this.data]
            } else {
              tmp = this.data
            }
            const func = this.evalFunc || treeToArray
            const args = this.evalArgs ? Array.concat([tmp, this.expandAll], this.evalArgs) : [tmp, this.expandAll]
            return func.apply(null, args)
          }
        },
        methods: {
          showRow: function(row) {
            const show = (row.row.parent ? (row.row.parent._expanded && row.row.parent._show) : true)
            row.row._show = show
            return show ? 'animation:treeTableShow 1s;-webkit-animation:treeTableShow 1s;' : 'display:none;'
          },
          // 切换下级是否展开
          toggleExpanded: function(trIndex) {
            const record = this.formatData[trIndex]
            record._expanded = !record._expanded
          },
          // 图标显示
          iconShow(index, record) {
            let childrenKey = this.childrenKey
            return (index === 0 && record[childrenKey] && record[childrenKey].length > 0)
          }
        }
      }
      </script>
      <style rel="stylesheet/css">
        @keyframes treeTableShow {
          from {opacity: 0;}
          to {opacity: 1;}
        }
        @-webkit-keyframes treeTableShow {
          from {opacity: 0;}
          to {opacity: 1;}
        }
      </style>

      <style lang="scss" rel="stylesheet/scss" scoped>
        $color-blue: #2196F3;
        $space-width: 18px;
        .ms-tree-space {
          position: relative;
          top: 1px;
          display: inline-block;
          font-style: normal;
          font-weight: 400;
          line-height: 1;
          width: $space-width;
          height: 14px;
          &::before {
            content: ""
          }
        }
        .processContainer{
          width: 100%;
          height: 100%;
        }
        table td {
          line-height: 26px;
        }

        .tree-ctrl{
          position: relative;
          cursor: pointer;
          color: $color-blue;
          margin-left: -$space-width;
        }
      </style>
